The present invention relates to circulating fluidized bed boilers and pertains particularly to a combined cycle power plant incorporating an atmospheric circulating fluidized bed boiler and gasifier.
Power generation systems combining a gas turbine and steam power plant with a fluidized bed furnace are known. Systems employing second generation pressurized fluidized bed technology have received substantial recent attention. In those systems, a pressurized fluidized bed combustion chamber burns a solid fuel such as coal to power a steam turbine, which in turn drives an electric generator. A gas turbine portion of the power plant is powered by high temperature compressed gas to drive another electric generator for increased power. Heat for the gas turbine system is provided to the gas turbine expansion chamber using gas produced by a gasifier or using natural gas.
In these prior art systems, high temperature filtering is required in the gas line to eliminate combustion particulates. Refractory lined pipes are further required because of the high temperature of the combustion gas. In addition, NO.sub.x reduction efforts are required in the gas turbine cycle.
Accordingly, an improved combined cycle power generation plant which overcomes the foregoing disadvantages would be desirable.